I went with Sapphire too. I've heard negative things about their customer service, but as I have not had to deal with them (all the cards worked great) and their Vapor X line, I give them the win. XFX has a nice warranty, and I have one of their 4850s which works great, but I have hear negatives about their quality (which I am sure will improve with time, since as you said they are new to the ATI game).